Radio communication device and radio communication system

ABSTRACT

Tablet PC (10) includes communication units (111, 112), antenna terminal (T1) used to receive one of first and second signals, antenna terminal (T2) used to receive another one of the first and second signals, terminal switch (40) configured to perform switching between a first coupling state in which communication unit (111) and terminal (T1) are coupled, and communication unit (112) and terminal (T2) are coupled, and a second coupling state in which communication unit (111) and terminal (T2) are coupled, and communication unit (112) and terminal (T1) are coupled, and controller (30) configured to control terminal switch (40) so as to switch to the first coupling state when terminal (T1) receives the first signal, and terminal (T2) receives the second signal, and to control terminal switch (40) so as to switch to the second coupling state when terminal (T1) receives the second signal, and terminal (T2) receives the first signal.

BACKGROUND 1. Technical Field

The present disclosure relates to a radio communication device and aradio communication system, which are capable of performing radiocommunications using external antennas.

2. Description of the Related Art

PTL 1 discloses a radio communication device including an internalantenna provided inside of a housing, and an external antenna providedoutside of the housing. The radio communication device measuresreception electric field levels (reception sensitivity) of the internalantenna and the external antenna, and switches and selects one of theinternal antenna and the external antenna, whichever has a highestreception electric field level.

CITATION LIST Patent Literature

PTL 1: Unexamined Japanese Patent Publication No. 2004-356798

SUMMARY

A radio communication device according to the present disclosureincludes first and second communication units, a first antenna terminalused to receive one of first and second signals, a second antennaterminal used to receive another one of the first and second signals, aterminal switch configured to perform switching between a first couplingstate in which the first communication unit and the first antennaterminal are coupled, and the second communication unit and the secondantenna terminal are coupled, and a second coupling state in which thefirst communication unit and the second antenna terminal are coupled,and the second communication unit and the first antenna terminal arecoupled, and a controller configured to control the terminal switch soas to switch to the first coupling state when in a first reception statein which the first antenna terminal receives the first signal, and thesecond antenna terminal receives the second signal, and to control theterminal switch so as to switch to the second coupling state when in asecond reception state in which the first antenna terminal receives thesecond signal, and the second antenna terminal receives the firstsignal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view when information processing device 1 according to afirst exemplary embodiment is mounted in vehicle 2 equipped withexternal antennas 3 ₁, 3 ₂;

FIG. 2 is an external view of information processing device 1 accordingto the first exemplary embodiment;

FIG. 3 is a view illustrating a configuration of tablet personalcomputer (PC) 10 shown in FIG. 2;

FIG. 4 is a view illustrating a configuration of holder 220 of base 20shown in FIG. 2;

FIG. 5 is a block diagram illustrating an electrical configuration in afirst mounting state of information processing device 1 according to thefirst exemplary embodiment;

FIG. 6 is a block diagram illustrating an electrical configuration in asecond mounting state of information processing device 1 according tothe first exemplary embodiment;

FIG. 7 is a view illustrating electrical couplings between controllers30, 35 in the first mounting state;

FIG. 8 is a view illustrating electrical couplings between controllers30, 35 in the second mounting state;

FIG. 9 is a block diagram illustrating an electrical configuration in afirst mounting state of information processing device 1A according to asecond exemplary embodiment;

FIG. 10 is a block diagram illustrating an electrical configuration in asecond mounting state of information processing device 1A according tothe second exemplary embodiment;

FIG. 11 is a view illustrating electrical couplings between controllers30A, 35A in the first mounting state; and

FIG. 12 is a view illustrating electrical couplings between controllers30A, 35A in the second mounting state.

DETAILED DESCRIPTION

Exemplary embodiments will be described herein in detail with referenceto the drawings appropriately. However, detailed descriptions more thannecessary might be sometimes omitted. For example, in some cases,detailed description of already well-known items and repeateddescription with respect to substantially the same configuration will beomitted. These omissions are made to avoid unnecessary redundancy of thefollowing description, and to facilitate the understanding of thoseskilled in the art. Note that the inventor(s) of the present disclosureprovide the accompanying drawings and the following description in orderto allow those skilled in the art to fully understand the presentdisclosure, and do not intend to limit the subject matter as describedin the appended claims.

Reasons of why the present disclosure has been invented A tablet PCdescribed below includes two communication units, i.e., a transmissionand reception communication unit (a radio communication moduleconforming to a communication system such as Bluetooth (registeredtrademark, the same hereinafter), Wi-Fi (IEEE802.11), third generationmobile communication system (3G), or Long-Term Evolution (LTE)), and areception exclusive communication unit (a radio communication moduleconforming to a communication system such as Global Positioning System(GPS)). For the tablet PC, the transmission and reception communicationunit needs to be coupled with a transmission and reception antenna, andthe reception exclusive communication unit needs to be coupled with areception exclusive antenna. In addition, in this case, the tablet PCneeds to be equipped with two antenna terminals for using two externalantennas, i.e., the transmission and reception antenna and the receptionexclusive antenna.

The inventors of the present disclosure have assumed that the tablet PCis coupled to a base mounted on a vehicle, for example, and thencoupled, via the base, to external antennas mounted on the vehicle.

The inventors of the present disclosure have assumed a system capable ofcoupling the tablet PC in two different orientations with respect to thebase. A problem underlie in the system is that, when the tablet PC iscoupled in one of the different orientations with respect to the base,coupling relations of the two antenna terminals to the two externalantennas might differ, and thus the relations of the two antennaterminals to two signals to be respectively received by the two externalantennas might be reversed. Therefore, the relations of the twocommunication units to two signals to be received by the two externalantennas might also be reversed, and thus signals respectivelycorresponding to the communication units will no longer be received.

The present disclosure provides a radio communication device includingtwo communication units and two antenna terminals, and a radiocommunication system, which are capable of receiving signalsrespectively corresponding to the two communication units, even if twosignals to be received by the two antenna terminals are reversed.

First Exemplary Embodiment

As an example radio communication system according to the presentdisclosure, an information processing device according to a firstexemplary embodiment will now be described herein with reference toFIGS. 1 to 8.

1-1. Configuration 1-1-1. Coupling Configuration of External Antennas

FIG. 1 is a view when information processing device 1 according to thefirst exemplary embodiment is mounted in vehicle 2 equipped withexternal antennas 3 ₁, 3 ₂. As shown in FIG. 1, information processingdevice 1 includes tablet PC (radio communication device) 10, and base 20mounted with tablet PC 10. Base 20 is mounted on vehicle 2. Base 20 hasa rear face coupled with two external antennas 3 ₁, 3 ₂ mounted onvehicle 2. Tablet PC 10 is coupled to two external antennas 3 ₁, 3 ₂ viabase 20. Information processing device 1 will now be described herein indetail.

1-1-2. Physical Configuration of Information Processing Device

FIG. 2 is an external view of information processing device 1 accordingto the first exemplary embodiment. As described above, informationprocessing device 1 includes tablet PC 10 and base 20. Tablet PC 10includes display (display unit) 100 on its front face. Display 100includes touch panel (operating unit) 110.

Base 20 includes keyboard unit 210 including keyboard 211, touch pad212, and operation buttons 213, and holder 220 for mounting tablet PC10. Keyboard unit 210 and holder 220 are coupled by hinges 230. Holder220 is provided with release lever 240. Release lever 240 is anoperating member to be operated to remove tablet PC 10 attached toholder 220 from holder 220. Tablet PC 10 can be removed from holder 220by sliding release lever 240 to unlock.

FIG. 3 is a view illustrating a configuration of tablet PC 10 shown inFIG. 2. As shown in FIG. 3, tablet PC 10 has a side face provided withfirst and second antenna terminals T₁, T₂ and first control terminalT₁₁. First and second antenna terminals T₁, T₂ are symmetricallyprovided in a left-right direction of tablet PC 10. First controlterminal T₁₁ is provided at an approximately center in the left-rightdirection of tablet PC 10 between first and second antenna terminals T₁,T₂. First and second antenna terminals T₁, T₂ are coaxial connectors,for example, and first control terminal T₁₁ is a connector having 25pins, for example.

FIG. 4 is a view illustrating a configuration of holder 220 of base 20shown in FIG. 2. As shown in FIG. 4, holder 220 of base 20 includesthird and fourth antenna terminals T₃, T₄ and second control terminalT₂₁. Third and fourth antenna terminals T₃, T₄ are symmetricallyprovided in a left-right direction of holder 220. Second controlterminal T₂₁ is provided at an approximately center in the left-rightdirection of holder 220 between third and fourth antenna terminals T₃,T₄. Third and fourth antenna terminals T₃, T₄ are coaxial connectors,for example, and second control terminal T₂₁ is a connector having 25pins, for example.

Tablet PC 10 is detachable with respect to base 20. Tablet PC 10 can beseparated from base 20 for use as a solo unit (e.g., see FIG. 3). TabletPC 10 can be mounted on holder 220 of base 20 for use as a laptop PC(e.g., see FIG. 2).

Since tablet PC 10 and base 20 respectively have symmetrical terminalconfigurations, two mounting states are available when tablet PC 10 isattached to holder 220 of base 20. In a first mounting state, as shownin FIG. 2, tablet PC 10 is attached to holder 220 such that a front oftablet PC 10, in which display 100 and touch panel 110 are provided,faces keyboard unit 210 of base 20. On the other hand, in a secondmounting state, tablet PC 10 is attached to holder 220 in a mannerreversed (inside out) from the first mounting state.

1-1-3. Electrical Configuration of Information Processing Device

FIG. 5 is a block diagram illustrating an electrical configuration inthe first mounting state of information processing device 1 according tothe first exemplary embodiment. FIG. 6 is a block diagram illustratingan electrical configuration in the second mounting state of informationprocessing device 1 according to the first exemplary embodiment.

As shown in FIG. 5, in the first mounting state, first antenna terminalT₁ of tablet PC 10 is coupled to third antenna terminal T₃ of base 20,and second antenna terminal T₂ of tablet PC 10 is coupled to fourthantenna terminal T₄ of base 20. On the other hand, as shown in FIG. 6,in the second mounting state, first antenna terminal T₁ of tablet PC 10is coupled to fourth antenna terminal T₄ of base 20, and second antennaterminal T₂ of tablet PC 10 is coupled to third antenna terminal T₃ ofbase 20. In both of the first and second mounting states, first controlterminal T₁₁ of tablet PC 10 is coupled to second control terminal T₂₁of base 20.

Tablet PC 10 includes, in addition to first and second antenna terminalsT₁, T₂ and first control terminal T₁₁, first and second communicationunits 11 ₁, 11 ₂, first and second internal antennas 12 ₁, 12 ₂, firstand second antenna switches 13 ₁, 13 ₂, controller 30, and terminalswitch 40.

First communication unit 11 ₁ is a communication module for transmittingand receiving (or receiving only) configured to perform communicationsconforming to a communication system such as Bluetooth, Wi-Fi, 3G, orLTE. Second communication unit 11 ₂ is a reception exclusivecommunication module configured to perform communications conforming toGPS, for example. First communication unit 11 ₁ and second communicationunit 11 ₂ may be formed in a single communication module.

First internal antenna 12 ₁ is a transmission and reception antennaconforming to a communication system such as Bluetooth, Wi-Fi, 3G, orLTE. Second internal antenna 12 ₂ is a reception exclusive antenna usedto perform communications conforming to GPS, for example.

First antenna switch 13 ₁ follows an antenna switch signal (details willbe described later) received from base 20 to switch a coupling betweenfirst communication unit 11 ₁ and first internal antenna 12 ₁ orterminal switch 40 (i.e., first external antenna 3 ₁). Second antennaswitch 13 ₂ follows an antenna switch signal received from base 20 toswitch a coupling between second communication unit 11 ₂ and secondinternal antenna 12 ₂ or terminal switch 40 (i.e., second externalantenna 3 ₂).

Controller 30 is coupled to first control terminal T₁₁. Controller 30cooperates with first control terminal T₁₁, and controller 35 and secondcontrol terminal T₂₁ in base 20 to function as a detector configured todetect how tablet PC 10 is mounted on base 20. Controller 30 outputs aterminal switch signal indicative of how tablet PC 10 is mounted withrespect to base 20. For example, the terminal switch signal is set to“high” in the first mounting state, and is set to “low” in the secondmounting state.

Terminal switch 40 follows the terminal switch signal transmitted fromcontroller 30 to perform switching between a first coupling state inwhich first antenna switch 13 ₁ (i.e., first communication unit 11 ₁)and first antenna terminal T₁ are coupled, and second antenna switch 13₂ (i.e., second communication unit 11 ₂) and second antenna terminal T₂are coupled, and a second coupling state in which first antenna switch13 ₁ (i.e., first communication unit 11 ₁) and second antenna terminalT₂ are coupled, and second antenna switch 13 ₂ (i.e., secondcommunication unit 11 ₂) and first antenna terminal T₁ are coupled.

In the first mounting state shown in FIG. 5, terminal switch 40 performsswitching based on a terminal switch signal at the “high” leveltransmitted from controller 30 such that first antenna switch 13 ₁ iscoupled to first antenna terminal T₁, and second antenna switch 13 ₂ iscoupled to second antenna terminal T₂. On the other hand, in the secondmounting state shown in FIG. 6, terminal switch 40 performs switchingbased on a terminal switch signal at the “low” level transmitted fromcontroller 30 such that first antenna switch 13 ₁ is coupled to secondantenna terminal T₂, and second antenna switch 13 ₂ is coupled to firstantenna terminal T₁.

Base 20 includes, in addition to third and fourth antenna terminals T₃,T₄ and second control terminal T₂₁, fifth and sixth antenna terminalsT₅, T₆, switch 22, and controller 35.

Fifth and sixth antenna terminals T₅, T₆ are disposed on the rear faceof base 20. Fifth antenna terminal T₅ is coupled to third antennaterminal T₃ and first external antenna 3 ₁. Sixth antenna terminal T₆ iscoupled to fourth antenna terminal T₄ and second external antenna 3 ₂.

Therefore, in the first mounting state shown in FIG. 5, first antennaterminal T₁ of tablet PC 10 receives a first signal via first externalantenna 3 ₁, and second antenna terminal T₂ of tablet PC 10 receives asecond signal via second external antenna 3 ₂ (first reception state).On the other hand, in the second mounting state shown in FIG. 6, firstantenna terminal T₁ of tablet PC 10 receives the second signal viasecond external antenna 3 ₂, and second antenna terminal T₂ of tablet PC10 receives the first signal via first external antenna 3 ₁ (secondreception state).

The first signal is a signal conforming to a communication system suchas Bluetooth, Wi-Fi, 3G, or LTE, and first external antenna 3 ₁ is atransmission and reception antenna used to perform communicationsconforming to a communication system such as Bluetooth, Wi-Fi, 3G, orLTE. The second signal is a signal conforming to a communication systemsuch as GPS, and second external antenna 3 ₂ is a reception exclusiveantenna used to perform communications conforming to GPS, for example.

Switch 22 is a switch used by a user to specify whether first and secondinternal antennas 12 ₁, 12 ₂ are used or first and second externalantennas 3 ₁, 3 ₂ are used on tablet PC 10. Switch 22 is a mechanicalswitch provided to base 20, and is manually operated by the user, forexample. Switch 22 transmits to tablet PC 10 an antenna switch signalindicative of a state of switch 22. The antenna switch signal is set to“high” when internal antennas are set to be used, using switch 22, andis set to “low” when external antennas are set to be used.

Controller 35 is coupled to switch 22 and second control terminal T₂₁.Controller 35 cooperates with second control terminal T₂₁, andcontroller 30 and first control terminal T₁₁ in tablet PC 10 to functionas a detector configured to detect how tablet PC 10 is mounted on base20.

1-2. Operation

Operation of information processing device 1 and tablet PC 10 configuredas described above will now be described herein.

First, how controllers 30, 35 and first and second control terminalsT₁₁, T₂₁ detect the first mounting state of tablet PC 10 with respect tobase 20 and the second mounting state reversed from the first mountingstate will now be described herein. FIG. 7 is a view illustratingelectrical couplings between controllers 30, 35 in the first mountingstate. FIG. 8 is a view illustrating electrical couplings betweencontrollers 30, 35 in the second mounting state.

As shown in FIG. 7, in the first mounting state, pins P1 to P25 of firstcontrol terminal T₁₁ are respectively coupled to pins P1 to P25 ofsecond control terminal T₂₁. On the other hand, as shown in FIG. 8, inthe second coupling state, pins P1 to P25 of first control terminal T₁₁are respectively coupled to pins P25 to P1 of second control terminalT₂₁.

Controller 30 of tablet PC 10 includes embedded computer (EC) 33 servedas a control circuit, and P-channel transistors Tr11, Tr12.

Pins IO1, IO2 of EC 33 are terminals used to detect how tablet PC 10 ismounted on base 20. Pin IO1 of EC 33 is coupled to a source terminal oftransistor Tr11, and a drain terminal of transistor Tr11 is grounded. Agate terminal of transistor Tr11 is coupled to pin P9 of first controlterminal T₁₁, and is grounded via a resistance element. On the otherhand, pin IO2 of EC 33 is coupled to a source terminal of transistorTr12, and a drain terminal of transistor Tr12 is grounded. A gateterminal of transistor Tr12 is coupled to pin P17 of first controlterminal T₁₁, and is grounded via a resistance element.

In the first mounting state, as shown in FIG. 7, reference voltageV_(REF) is input from controller 35 of base 20, via pin P9, into thegate terminal of transistor Tr11, and thus transistor Tr11 is turnedoff. Therefore, pin IO1 of EC 33 is open. On the other hand, the gateterminal of transistor Tr12 is coupled to a ground potential via pinP17, and thus transistor Tr12 is turned on. Therefore, pin IO2 of EC 33is at a “low” level. As described above, when pin IO1 is open, and pinIO2 is at the low level, EC 33 detects the first mounting state, andtransmits to terminal switch 40 the terminal switch signal at the “high”level indicative of the first mounting state.

On the other hand, in the second coupling state, as shown in FIG. 8, thegate terminal of transistor Tr11 is coupled to the ground potential viapins P9 and P17, and thus transistor Tr11 is turned on. Therefore, pinIO1 of EC 33 is at a “low” level. On the other hand, reference voltageV_(REF) is input from controller 35 of base 20, via pins P17 and P9,into the gate terminal of transistor Tr12, and thus transistor Tr12 isturned off. Therefore, pin IO2 of EC 33 is open. As described above,when pin IO1 is at the low level, and pin IO2 is open, EC 33 detects thesecond mounting state, and transmits to terminal switch 40 the terminalswitch signal at the “low” level indicative of the second mountingstate.

Pins IO3, IO4 of EC 33 are terminals used to receive antenna switchsignals from switch 22. Pins IO3, IO4 are coupled to switch 22. In bothof the first and second mounting states, EC 33 receives the antennaswitch signal from switch 22 via pin IO3 or IO4.

Pins IO3, IO4 of EC 33 also detect that tablet PC 10 is solely used.When pins IO3, IO4 of EC 33 are open, EC 33 detects that tablet PC 10 isremoved from base 20, and pins P1, P25 of first control terminal T₁₁ areopen, and transmits an antenna switch signal at the “high” level tofirst and second antenna switches 13 ₁, 13 ₂.

1-2-1. Solo Unit State

When tablet PC 10 is solely used, as shown in FIG. 3, pins P1, P25 offirst control terminal T₁₁ and pins IO3, IO4 of EC 33 of controller 30shown in FIG. 7 are open. At this time, EC 33 controls first antennaswitch 13 ₁ such that first communication unit 11 ₁ is coupled to firstinternal antenna 12 ₁. Simultaneously, EC 33 controls second antennaswitch 13 ₂ such that second communication unit 11 ₂ is coupled tosecond internal antenna 12 ₂ (shown with broken lines in first andsecond antenna switches 13 ₁, 13 ₂ in FIG. 5).

Therefore, first communication unit 11 ₁ can use first internal antenna12 ₁ to perform communications, and second communication unit 11 ₂ canuse second internal antenna 12 ₂ to perform communications.

1-2-2. First Mounting State

As shown in FIGS. 2 and 5, when tablet PC 10 is attached to holder 220of base 20 in the first mounting state, first antenna terminal T₁ oftablet PC 10 is coupled to third antenna terminal T₃ of base 20, andsecond antenna terminal T₂ is coupled to fourth antenna terminal T₄ ofbase 20. At this time, as shown in FIG. 7, pins P1 to P25 of firstcontrol terminal T₁₁ are respectively coupled to pins P1 to P25 ofsecond control terminal T₂₁.

As shown in FIG. 7, the gate terminal of transistor Tr12 of controller30 is grounded, transistor Tr12 is turned on, and pin IO2 of EC 33 is at“low.” Simultaneously, reference voltage V_(REF) is input into the gateterminal of transistor Tr11, transistor Tr11 is turned off, and pin IO1of EC 33 is open. Upon the first mounting state is detected, EC 33 ofcontroller 30 transmits to terminal switch 40 the terminal switch signalat the “high” level to control terminal switch 40 such that, as shown inFIG. 5, first antenna switch 13 ₁ (i.e., first communication unit 11 ₁)is coupled to first antenna terminal T₁, and second antenna switch 13 ₂(i.e., second communication unit 11 ₂) is coupled to second antennaterminal T₂.

Therefore, first communication unit 11 ₁ can use first external antenna3 ₁ to perform communications, and second communication unit 11 ₂ canuse second external antenna 3 ₂ to perform communications.

When tablet PC 10 is mounted on base 20 for use in a vehicle,communications using first and second internal antennas 12 ₁, 12 ₂become difficult because the vehicle is internally shielded. In thiscase, a user operates switch 22 such that first and second externalantennas 3 ₁, 3 ₂ are available. Therefore, the antenna switch signal at“low” is transmitted from switch 22, and is input into pins IO3, IO4 ofEC 33 of controller 30. Therefore, EC 33 transmits the antenna switchsignal at the “low level” to first antenna switch 13 ₁ to control firstantenna switch 13 ₁ such that first communication unit 11 ₁ is coupledto terminal switch 40 (i.e., first external antenna 3 ₁).Simultaneously, EC 33 transmits the antenna switch signal at the “lowlevel” to second antenna switch 13 ₂ to control second antenna switch 13₂ such that second communication unit 11 ₂ is coupled to terminal switch40 (i.e., second external antenna 3 ₂) (shown with solid lines in firstand second antenna switches 13 ₁, 13 ₂ in FIG. 5).

When the user operates switch 22 such that first and second internalantennas 12 ₁, 12 ₂ are available, the antenna switch signal at “high”is transmitted from switch 22. Therefore, the signal at the high levelis input into pins IO3, IO4 of EC 33 of controller 30. Therefore, EC 33transmits the antenna switch signal at the “high level” to first antennaswitch 13 ₁ to control first antenna switch 13 ₁ such that firstcommunication unit 11 ₁ is coupled to first internal antenna 12 ₁.Simultaneously, EC 33 transmits the antenna switch signal at the “highlevel” to second antenna switch 13 ₂ to control second antenna switch 13₂ such that second communication unit 11 ₂ is coupled to second internalantenna 12 ₂ (shown with dotted lines in first and second antennaswitches 13 ₁, 13 ₂ in FIG. 5).

Therefore, first communication unit 11 ₁ can use one of first externalantenna 3 ₁ and first internal antenna 12 ₁ to perform communications,and second communication unit 11 ₂ can use one of second externalantenna 3 ₂ and second internal antenna 12 ₂ to perform communications.

1-2-3. Second Mounting State

As shown in FIG. 6, when tablet PC 10 is attached to holder 220 of base20 in the second mounting state, first antenna terminal T₁ of tablet PC10 is coupled to fourth antenna terminal T₄ of base 20, and secondantenna terminal T₂ is coupled to third antenna terminal T₃ of base 20.At this time, as shown in FIG. 8, pins P1 to P25 of first controlterminal T₁₁ are respectively coupled to pins P25 to P1 of secondcontrol terminal T₂₁.

At this time, the gate terminal of transistor Tr11 of controller 30 isgrounded, transistor Tr11 is turned on, and pin IO1 of EC 33 is at the“low” level. Simultaneously, reference voltage V_(REF) is input into thegate terminal 10 of transistor Tr12, transistor Tr12 is turned off, andpin IO2 of EC 33 is open. Upon the second coupling state is detected, EC33 of controller 30 transmits to terminal switch 40 the terminal switchsignal at the “low” level to control terminal switch 40 such that, asshown in FIG. 6, first antenna switch 13 ₁ (i.e., first communicationunit 11 ₁) is coupled to second antenna terminal T₂, and second antennaswitch 13 ₂ (i.e., second communication unit 11 ₂) is coupled to firstantenna terminal T₁.

Therefore, even in the second mounting state, similar to the firstmounting state, first communication unit 11 ₁ can use first externalantenna 3 ₁ to perform communications, and second communication unit 11₂ can use second external antenna 3 ₂ to perform communications.

1-3. Effects and Other Benefits

As described above, in this exemplary embodiment, tablet PC (radiocommunication device) 10 includes first and second communication units11 ₁, 11 ₂, first and second antenna terminals T₁, T₂, terminal switch40, and controller 30. First antenna terminal T₁ receives one of firstand second signals, and second antenna terminal T₂ receives another oneof the first and second signals. Terminal switch 40 performs switchingbetween a first coupling state in which first communication unit 11 ₁and first antenna terminal T₁ are coupled, and second communication unit11 ₂ and second antenna terminal T₂ are coupled, and a second couplingstate in which first communication unit 11 ₁ and second terminal T₂ arecoupled, and second communication unit 11 ₂ and first antenna terminalT₁ are coupled. Controller 30 controls terminal switch 40 to switch tothe first coupling state when in the first reception state in whichfirst antenna terminal T₁ receives the first signal, and second antennaterminal T₂ receives the second signal, and to switch to the secondcoupling state when in the second reception state in which first antennaterminal T₁ receives the second signal, and second antenna terminal T₂receives the first signal.

In this exemplary embodiment, information processing device (radiocommunication system) 1 includes, as described above, tablet PC (radiocommunication device) 10 and base 20. Base 20 allows tablet PC 10 to bedetachably mounted, and includes third antenna terminal T₃ used tooutput the first signal, and fourth antenna terminal T₄ used to outputthe second signal. In the above-described first reception state, tabletPC 10 is mounted on base 20 such that first antenna terminal T₁ iscoupled to third antenna terminal T₃, and second antenna terminal T₂ iscoupled to fourth antenna terminal T₄ (first mounting state). In theabove-described second reception state, tablet PC 10 is mounted on base20 such that first antenna terminal T₁ is coupled to fourth antennaterminal T₄, and second antenna terminal T₂ is coupled to third antennaterminal T₃ (second mounting state).

Therefore, even when tablet PC (radio communication device) 10 isattached to base 20 in the second mounting state reversed from the firstmounting state (rotated by 180°), and signals to be received by firstantenna terminal T₁ and second antenna terminal T₂ are reversed, arelation between first communication unit 11 ₁ and the first signal anda relation between second communication unit 11 ₂ and the second signalare maintained, similar to the case when tablet PC 10 is attached tobase 20 in the first mounting state.

In other words, even when couplings of first and second antennaterminals T₁, T₂ to first and second external antennas 3 ₁, 3 ₂ arereversed, a coupling relation between first communication unit 11 ₁ andfirst external antenna 3 ₁ and a coupling relation between secondcommunication unit 11 ₂ and second external antenna 3 ₂ are maintained.

Second Exemplary Embodiment

The first exemplary embodiment has described the configuration in whichtablet PC 10 includes terminal switch 40. In contrast, a secondexemplary embodiment describes a configuration in which a base includesa terminal switch. The second exemplary embodiment will now be describedherein with reference to FIGS. 9 to 12.

FIG. 9 is a block diagram illustrating an electrical configuration in afirst mounting state of information processing device 1A according tothe second exemplary embodiment. FIG. 10 is a block diagram illustratingan electrical configuration in a second mounting state of informationprocessing device 1A according to the second exemplary embodiment.Information processing device 1A includes tablet PC 10A and base 20A.

Tablet PC 10A according to the second exemplary embodiment differs fromtablet PC 10 according to the first exemplary embodiment in terms ofthat terminal switch 40 is not included, first antenna switch 13 ₁ forfirst communication unit 11 ₁ is always coupled to first antennaterminal T₁, and second antenna switch 13 ₂ for second communicationunit 11 ₂ is always coupled to second antenna terminal T₂.

Tablet PC 10A according to the second exemplary embodiment includescontroller 35A. Controller 35A is coupled to first control terminal T₁₁.Controller 35A cooperates with first control terminal T₁₁, andcontroller 30A and second control terminal T₂₁ in base 20A to functionas a detector configured to detect how tablet PC 10A is mounted on base20A.

Base 20A according to the second exemplary embodiment differs from base20 according to the first exemplary embodiment in terms of that terminalswitch 40 is further included. Terminal switch 40 follows a terminalswitch signal transmitted from controller 30A to perform switchingbetween a first coupling state in which third antenna terminal T₃ andfifth antenna terminal T₅ (i.e., first external antenna 3 ₁) arecoupled, and fourth antenna terminal T₄ and sixth antenna terminal T₆(i.e., second external antenna 3 ₂) are coupled, and a second couplingstate in which third antenna terminal T₃ and sixth antenna terminal T₆(i.e., second external antenna 3 ₂) are coupled, and fourth antennaterminal T₄ and fifth antenna terminal T₅ (i.e., first external antenna3 ₁) are coupled.

Controller 30A of base 20A includes EC 33 and P-channel transistorsTr11, Tr12.

Pins IO1, IO2 of EC 33 are terminals used to detect how tablet PC 10A ismounted on base 20A. Pin IO1 is coupled to a source terminal oftransistor Tr11. A drain terminal of transistor Tr11 is grounded. A gateterminal of transistor Tr11 is coupled to pin P9 of second controlterminal T₂₁, and is grounded via a resistance element. On the otherhand, pin IO2 is coupled to a source terminal of transistor Tr12. Adrain terminal of transistor Tr12 is grounded. A gate terminal oftransistor Tr12 is coupled to pin P17 of second control terminal T₂₁,and is grounded via a resistance element.

Controller 35A of tablet PC 10A includes EC 36. Pins IO3, IO4 of EC 36are terminals used to detect a state of switch 22. Pins IO3, IO4 of EC36 are coupled to switch 22. In both of the first and second mountingstates, EC 36 receives an antenna switch signal from switch 22 via pinIO3 or IO4.

In the first mounting state shown in FIG. 9, controller 30A outputs aterminal switch signal at a “high” level. Terminal switch 40 follows theterminal switch signal to couple third antenna terminal T₃ to fifthantenna terminal T₅, and to couple fourth antenna terminal T₄ to sixthantenna terminal T₆. On the other hand, in the second mounting stateshown in FIG. 10, controller 30A outputs a terminal switch signal at a“low” level. Terminal switch 40 follows the terminal switch signal tocouple third antenna terminal T₃ to sixth antenna terminal T₆, and tocouple fourth antenna terminal T₄ to fifth antenna terminal T₅.

Controller 30A of base 20A is coupled to switch 22 and second controlterminal T₂₁. Controller 30A cooperates with second control terminalT₂₁, and controller 35A and first control terminal T₁₁ in tablet PC 10Ato function as a detector configured to detect how tablet PC 10A ismounted on base 20A.

How controllers 30A, 35A and first and second control terminals T₁₁, T₂₁detect the first and second mounting states of tablet PC 10A withrespect to base 20A will now be described herein. FIG. 11 is a viewillustrating electrical couplings between controllers 30A, 35A in thefirst mounting state. FIG. 12 is a view illustrating electricalcouplings between controllers 30A, 35A in the second mounting state.

As shown in FIG. 11, in the first mounting state, pins P1 to P25 offirst control terminal T₁₁ are respectively coupled to pins P1 to P25 ofsecond control terminal T₂₁. On the other hand, as shown in FIG. 12, inthe second mounting state, pins P1 to P25 of first control terminal T₁₁are respectively coupled to pins P25 to P1 of second control terminalT₂₁.

In the first mounting state, as shown in FIG. 11, reference voltageV_(REF) is input from controller 35A of tablet PC 10A, via pin P9, intothe gate terminal of transistor Tr11, and thus transistor Tr11 is turnedoff. Therefore, pin IO1 of EC 33 is open. On the other hand, the gateterminal of transistor Tr12 is coupled to a ground potential via pinP17, and thus transistor Tr12 is turned on. Therefore, pin IO2 of EC 33is at a “low” level. As described above, when pin IO1 is open, and pinIO2 is at the low level, EC 33 detects the first mounting state, andtransmits to terminal switch 40 the terminal switch signal at the “high”level indicative of the first mounting state.

On the other hand, in the second coupling state, as shown in FIG. 12,the gate terminal of transistor Tr11 is coupled to a ground potentialvia pins P9 and P17, and thus transistor Tr11 is turned on. Therefore,pin IO1 of EC 33 is at a “low” level. On the other hand, referencevoltage V_(REF) is input from controller 35A of tablet PC 10A, via pinsP17 and P9, into the gate terminal of transistor Tr12, and thustransistor Tr12 is turned off. Therefore, pin IO2 of EC 33 is open. Asdescribed above, when pin IO1 is at the low level, and pin IO2 is open,EC 33 detects the second mounting state, and transmits to terminalswitch 40 the terminal switch signal at the “low” level indicative ofthe second mounting state.

First Mounting State

When tablet PC 10A is attached to a holder of base 20A in the firstmounting state, as shown in FIG. 9, first antenna terminal T₁ of tabletPC 10A is coupled to third antenna terminal T₃ of base 20A, and secondantenna terminal T₂ is coupled to fourth antenna terminal T₄ of base20A. At this time, as shown in FIG. 11, pins P1 to P25 of first controlterminal T₁₁ are respectively coupled to pins P1 to P25 of secondcontrol terminal T₂₁.

At this time, as shown in FIG. 11, a potential at the gate terminal oftransistor Tr12 of controller 30A reaches the ground potential,transistor Tr12 is turned on, and pin IO2 of EC 33 is at “low.”Simultaneously, reference voltage V_(REF) is input into the gateterminal of transistor Tr11, transistor Tr11 is turned off, and pin IO1of EC 33 is open. Based on the states of pins IO1, IO2 as describedabove, EC 33 of controller 30A detects the first mounting state, andtransmits to terminal switch 40 the terminal switch signal at the “high”level. Therefore, as shown in FIG. 9, terminal switch 40 is controlledsuch that third antenna terminal T₃ (i.e., first communication unit 11₁) is coupled to fifth antenna terminal T₅, and fourth antenna terminalT₄ (i.e., second communication unit 11 ₂) is coupled to sixth antennaterminal T₆.

Therefore, first communication unit 11 ₁ can use first external antenna3 ₁ to perform communications, and second communication unit 11 ₂ canuse second external antenna 3 ₂ to perform communications.

Second Mounting State

On the other hand, when tablet PC 10A is attached to the holder of base20A in the second mounting state, as shown in FIG. 10, first antennaterminal T₁ of tablet PC 10A is coupled to fourth antenna terminal T₄ ofbase 20A, and second antenna terminal T₂ is coupled to third antennaterminal T₃ of base 20A. At this time, as shown in FIG. 12, pins P1 toP25 of first control terminal T₁₁ are respectively coupled to pins P25to P1 of second control terminal T₂₁.

At this time, as shown in FIG. 12, a potential at the gate terminal oftransistor Tr11 of controller 30A reaches the ground potential,transistor Tr11 is turned on, and pin IO1 of EC 33 is at the “low”level. Simultaneously, reference voltage V_(REF) is input into the gateterminal of transistor Tr12 of controller 30A, transistor Tr12 is turnedoff, and pin IO2 of EC 33 is open. Based on the states of pins IO1, IO2as described above, EC 33 of controller 30A detects the second couplingstate, and transmits to terminal switch 40 the terminal switch signal atthe “low” level. Therefore, as shown in FIG. 10, terminal switch 40 iscontrolled such that third antenna terminal T₃ (i.e., firstcommunication unit 11 ₁) is coupled to sixth antenna terminal T₆, andfourth antenna terminal T₄ (i.e., second communication unit 11 ₂) iscoupled to fifth antenna terminal T₅.

Therefore, even in the second mounting state, similar to the firstmounting state, first communication unit 11 ₁ can use first externalantenna 3 ₁ to perform communications, and second communication unit 11₂ can use second external antenna 3 ₂ to perform communications.

As described above, also in this exemplary embodiment, even when tabletPC (radio communication device) 10A is mounted on base 20A in the secondmounting state, and signals to be received by first antenna terminal T₁and second antenna terminal T₂ are reversed, a relation between firstcommunication unit 11 ₁ and the first signal and a relation betweensecond communication unit 11 ₂ and the second signal are maintained,similar to the case when tablet PC 10A is mounted on base 20A in thefirst mounting state.

In other words, even when couplings of first and second antennaterminals T₁, T₂ to first and second external antennas 3 ₁, 3 ₂ arereversed, a coupling relation between first communication unit 11 ₁ andfirst external antenna 3 ₁ and a coupling relation between secondcommunication unit 11 ₂ and second external antenna 3 ₂ are maintained.

Other Exemplary Embodiments

As above, the first and second exemplary embodiments have been describedas illustration of the technique disclosed in the present application.However, the technique of the present disclosure is not limited to thefirst and second exemplary embodiments, but is applicable to anotherexemplary embodiment in which a change, a replacement, an addition, oran omission is appropriately made. A new exemplary embodiment can alsobe made by a combination of the components described in the first andsecond exemplary embodiments.

The exemplary embodiments have described, as first communication unit 11₁, a communication module for transmitting and receiving (or receivingonly) configured to perform communications conforming to a communicationsystem such as Bluetooth, Wi-Fi, third generation mobile communicationsystem (3G), or Long Term Evolution (LTE), and, as second communicationunit 11 ₂, a reception exclusive communication module configured toperform communications conforming to GPS, for example. However, thepresent disclosure is not limited to these communication modules. Firstand second communication units 11 ₁, 11 ₂ according to the presentdisclosure may be communication modules for transmitting and receiving(or receiving only) configured to perform communications conforming toone of communication systems including Global Positioning System (GPS),Bluetooth, Wi-Fi, 3G and LTE. In this case, first and second internalantennas 12 ₁, 12 ₂ and first and second external antennas 3 ₁, 3 ₂ maybe transmission and reception antennas conforming to a communicationsystem corresponding to a communication system to which first and secondcommunication units 11 ₁, 11 ₂ conform. In such an exemplary embodiment,the idea of the present disclosure can be applied when a communicationsystem to which first communication unit 11 ₁ conforms and acommunication system to which second communication unit 11 ₂ conformsdiffer from each other.

Each of the exemplary embodiments has described a tablet PC includingtwo communication units and two antenna terminals. However, the presentdisclosure is not limited to these components. The idea of the presentdisclosure can be applied to various devices including two communicationunits and two antenna terminals, in which signals to be received by thetwo antenna terminals are reversed.

The exemplary embodiments have been described above and exemplified asthe technique of the present disclosure. The accompanying drawings anddetailed description have been provided for this purpose. Accordingly,the components described in the appended drawings and the detaileddescription include, in order to exemplifying the above describedtechnique, not only essential components, but also components that arenot essential. Therefore, it should not be immediately construed thatthese components that are not essential are essential even if thecomponents are described in the appended drawings and the detaileddescription. Since the above-described exemplary embodiments are forexemplifying the technique of the present disclosure, variousmodifications, replacements, additions, and omissions can be made withinthe scope of the appended claims or of their equivalents.

The present disclosure is applicable to radio communication devicescapable of performing radio communications using external antennas.

What is claimed is:
 1. A radio communication device comprising: firstand second communication units; a first antenna terminal used to receiveone of first and second signals; a second antenna terminal used toreceive another one of the first and second signals; a terminal switchconfigured to perform switching between a first coupling state in whichthe first communication unit and the first antenna terminal are coupled,and the second communication unit and the second antenna terminal arecoupled, and a second coupling state in which the first communicationunit and the second antenna terminal are coupled, and the secondcommunication unit and the first antenna terminal are coupled; and acontroller configured to control the terminal switch so as to switch tothe first coupling state when in a first reception state in which thefirst antenna terminal receives the first signal, and the second antennaterminal receives the second signal, and to control the terminal switchso as to switch to the second coupling state when in a second receptionstate in which the first antenna terminal receives the second signal,and the second antenna terminal receives the first signal.
 2. The radiocommunication device according to claim 1, wherein each of the firstcommunication unit and the second communication unit is a communicationmodule for transmitting and receiving or for receiving only, and acommunication system to which the first communication unit conforms anda communication system to which the second communication unit conformsdiffer from each other.
 3. The radio communication device according toclaim 1, wherein the first signal is a signal to be received by a firstexternal antenna, and the second signal is a signal to be received by asecond external antenna.
 4. The radio communication device according toclaim 1, further comprising: a first internal antenna; a second internalantenna; a first antenna switch configured to couple the firstcommunication unit to the first internal antenna or the terminal switch;and a second antenna switch configured to couple the secondcommunication unit to the second internal antenna or the terminalswitch.
 5. The radio communication device according to claim 2, whereineach of the first communication unit and the second communication unitis the communication module conforming to one of communication systemsof Global Positioning System (GPS), Bluetooth, Wi-Fi, third generationmobile communication system (3G), and Long-Term Evolution (LTE).
 6. Aradio communication system comprising: the radio communication deviceaccording to claim 1; and a base detachably mounted with the radiocommunication device, the base including: a third antenna terminal usedto output the first signal; and a fourth antenna terminal used to outputthe second signal.
 7. The radio communication system according to claim6, further comprising a detector configured to detect the firstreception state and the second reception state.
 8. A radio communicationsystem comprising: a radio communication device; and a base mounted withthe radio communication device, wherein the radio communication deviceincludes first and second communication units, a first antenna terminalcoupled to the first communication unit, and a second antenna terminalcoupled to the second communication unit, and wherein the base includesa third antenna terminal to be coupled to one of the first and secondantenna terminals, a fourth antenna terminal to be coupled to anotherone of the first and second antenna terminals, a fifth antenna terminalused to receive a first signal, a sixth antenna terminal used to receivea second signal, a terminal switch configured to perform switchingbetween a first coupling state in which the third antenna terminal andthe fifth antenna terminal are coupled, and the fourth antenna terminaland the sixth antenna terminal are coupled, and a second coupling statein which the third antenna terminal and the sixth antenna terminal arecoupled, and the fourth antenna terminal and the fifth antenna terminalare coupled, and a controller configured to control the terminal switch,and wherein the controller controls the terminal switch so as to switchto the first coupling state when the radio communication device ismounted on the base such that the first antenna terminal and the thirdantenna terminal are coupled, and the second antenna terminal and thefourth antenna terminal are coupled, and so as to switch to the secondcoupling state when the radio communication device is mounted on thebase such that the first antenna terminal and the fourth antennaterminal are coupled, and the second antenna terminal and the thirdantenna terminal are coupled.